But I am also starting my own company, my dream job. How do I communicate that information to my co-workers? How will they react? Will it be viewed as disloyalty or lack of commitment by my boss?

I decided early on to be open and completely honest with my coworkers about my other work. There are risks. But I truly have nothing to hide or be ashamed of. My dream job does not conflict or interfere with my day job. So I talk a little about my dreams with my coworkers.

They have been excited for me and very encouraging. They have offered to help in small ways.